The correct answer is option 4: Banas. Banas is not a tributary of the river Luni.

To understand why, let`s look at the other options provided:

Option 1: Khari. Khari is a tributary of the river Luni.

Option 2: Sukri. Sukri is a tributary of the river Luni.

Option 3: Jawai. Jawai is a tributary of the river Luni.

Therefore, the only option that is not a tributary of the river Luni is Banas.

The Luni River is a crucial river in the Indian state of Rajasthan. It originates in the Pushkar valley of the Aravalli Range and flows through Rajasthan, ultimately draining into the Rann of Kutch in Gujarat.

It is important to note that Banas is a river in Rajasthan, but it does not flow into the Luni River. Instead, it is a tributary of the Chambal River.